1. Field of the Invention
The present invention relates to technologies for performing connection authentication in information processing apparatuses and function expansion devices that are capable of wired connection and wireless connection.
2. Description of the Related Art
Portable information terminals, such as personal digital assistants (PDAs) and cellular telephones, provided with a function expansion device including a speaker, a microphone, a headphone, a keyboard, a mouse, an external storage device, a laser bar code reader, a camera adapter, a global positioning system (GPS) adapter, and various other wireless communication adapters to use new functions as well as existing functions are known.
A function expansion device is installed in a portable information terminal by inserting the function expansion device into an installation part of the portable information terminal. Performing wired connection via a signal line for information exchange enables information processed in the function expansion device to be received in the portable information terminal and enables information processed in the portable information terminal to be received in the function expansion device.
In many cases, for a combination of a portable information terminal and an input/output system function expansion device, such as a combination of a PDA and a camera adapter or a combination of a PDA and a headphone, wireless connection provides a higher degree of flexibility in a positional relationship of the portable information terminal and the function expansion device. Thus, wireless connection is more convenient and applicable for various uses, compared with wired connection.
In view of such circumstances, methods for performing information exchange by connecting a portable information terminal and a function expansion device using a local wireless communication system has been used.
Information exchange performed by wirelessly connecting a portable information terminal and a function expansion device using a local wireless communication system provides a higher flexibility in usage. However, since portable information terminals and function expansion devices that are provided with the same type of wireless communication system can be wirelessly connected to each other, an unwanted terminal may be connected to a portable information terminal and information may be captured by the unwanted terminal. Also, there are significantly more possibilities that unnecessary information is input and that information being transferred between the portable information terminal and the function expansion device is secretly looked at, compared with wired connection.
In order to solve the above problems, a procedure for using a personal identification number (a connection authentication code) is known. This procedure includes a method in which the same personal identification number is input to a portable information terminal and to a function expansion device, the personal identification numbers stored in the portable information terminal and the function expansion device are compared with each other when connection is performed, and connection is authenticated only when the personal identification number stored in the portable information terminal is equal to the personal identification number stored in the function expansion device, and a method in which transfer data is encrypted, locking is performed using a personal identification number, and a receiver decrypts the transfer data using the personal identification number as a key.
In the known procedure for using personal identification numbers, a user must input a personal identification number to a portable information terminal and to a function expansion device that are to be wirelessly connected to each other. Also, a user must consider a number sequence, a character sequence, or a combination of numbers and characters in order to create a personal identification number. Thus, creating a personal identification number is a very troublesome operation. Also, generally, personal identification numbers created by users are mostly guessable. Thus, users fear that their personal identification numbers will be guessed.